Water cactus every 2-3 weeks in summer and every 6-8 weeks — almost none in winter. The soil is a better guide than the calendar: Only when the soil is bone dry to the bottom. In winter, withholding entirely is the safer error.
A dead cactus is nearly always a drowned one. In winter it stops growing and goes dormant, so water given then simply sits there and rots the roots. If the body softens and the base blackens, cut back to healthy tissue, let the cut callus over for a few days, and replant into dry soil.
Every two or three years in spring, into dry soil — wait a week before watering.
Growing conditions
| Watering in summer | Every 2-3 weeks |
|---|---|
| Watering in winter | Every 6-8 weeks — almost none |
| How to tell it needs water | Only when the soil is bone dry to the bottom. In winter, withholding entirely is the safer error. |
| Light | Direct sun, four hours or more |
| Temperature | 10-35°C, above 5°C in winter |
| Humidity | The drier the better |
| Repotting | Every two or three years in spring, into dry soil — wait a week before watering. |
Troubleshooting
| Symptom | Likely cause | What to do |
|---|---|---|
| Soft body, blackened base | Root rot from overwatering | Cut back to firm tissue, dry for three to five days, then replant. |
| Growing thin and stretched at the top | Not enough light | Move it to a sunny window. |
| Whitened patches on the surface | Sunburn after a sudden move into strong light | Acclimatise it to strong sun over several days. |